1. Field of the Invention
Exemplary embodiments relate to a super high frequency (SHF)/extremely high frequency (EHF) band wireless transmission technology, and more particularly, to an apparatus and method that may resolve line of sight (LoS) limitations found in super high frequency (SHF)/extremely high frequency (EHF) band transmissions, by introducing the concepts of a multi-level relay topology and separation of control and traffic resource allocation.
2. Description of the Related Art
With an increase in an amount of mobile traffic, cell minimization has been pursued. A reduction of a cell radius causes inter-cell interference more often and results in more frequent handover, which may increase a system load, and in some instances, may raise a serious issue of a handover delay beyond an allowable limit.
Accordingly, there is a limitation on architectures using only cellular frequency bands, and in terms of development of new frequency resources, exploitation of super high frequency (SHF)/extremely high frequency (EHF) bands is being contemplated.
In a case of SHF/EHF bands, implementation is possible with a millimeter wave (mmWave) band-based narrow beam, so that interference and handover issues are alleviated to a great extent and cell micro-minimization is achieved. However, one of the unique properties of SHF/EHF bands, line of sight (LoS) communication, is also a limitation issue to be resolved.